Influence of Gd on the magnetic properties of amorphous (Fe1-xGdx)(80)B-20

Amorphous (Fe1-xGdx)(80)B-20 alloys have been prepared by melt spinning tec hnique and their magnetic properties have been studied. The Gd moment at 10 K is found to be 7 mu(B) which agrees with the theoretical value indicatin g a collinear spin structure. The magnetic compensation at 10 K occurs for x close to 0.195. The mean-field theory has been used to explain the temper ature dependence of the magnetization. The exchange interactions between Fe -Fe, Fe-Gd and Gd-Gd atom pairs have also been evaluated. From an analysis of the approach to saturation magnetization, the local random anisotropy co nstant K-L has been extracted. It is found that K-L decreases with increasi ng Gd concentration. This result suggests that the substitution of Fe with Gd seems to favor the increase of magnetic order by reducing the random ani sotropy.